As a method of imparting stereographic/patterns on base materials formed of papers or plastic sheets, synthetic leathers, etc., embossing process has been widely practiced from old days. The general method of an embossing process is to preheat a sheet-shaped material, impress a concavo-convex pattern from a stamping roll in which the specified pattern is carved, followed by cooling, and then, take up the product.
However, the conventional embossing process involves problems such as: (1) stamping rolls on which the specified patterns are carved, equal in number to said patterns, need to be prepared, inevitably resulting in high installation cost; (2) since the luster of the embossed surface is normally uniform, it is not easy to create subtle modelings and external appearances of perspective and stereographic patterns due to grades of luster by differentiating the luster part by part; (3) under roll forming technical restrictions, the freedom of the picture pattern is naturally limited; and (4) the stamping roll needs to be replaced every time the pattern is changed, with inevitable disadvantage in work efficiency, which is fatal particularly in the case of multi-item small amount production. This invention has been reached as a result of assiduous studies carried out in an effort to solve the aforementioned problems in this technical situation.